In the past, as a method of performing printing on the surface of a resin product, a metal product, or the like, pad printing has been known. In the pad printing, printing is performed as follows. First, after an ink is applied onto an intaglio plate with a printing pattern carved therein, the ink is pushed into the printing pattern of the intaglio plate by using a blade or the like and the ink on places other than the inside of the printing pattern is removed. Subsequently, a transfer pad having elasticity is pressed against the intaglio plate from above, so that the ink in the printing pattern is transferred to the transfer pad. Thereafter, the transfer pad with the printing pattern transferred thereto is pressed against a printing object, so that the ink forming the printing pattern is transferred to the printing object, whereby printing is performed.
Further, as a printing method on a printing object having a curved surface, a method is disclosed in which printing is directly performed on a planar original plate by an ink jet system, a viscosity increasing treatment is performed on the ink on the planar original plate, the ink is transferred from the planar original plate to a soft pad having a curved surface of a shape approximately similar to that of the printing curved surface of the printing object, and the soft pad is brought into contact with the printing surface of the printing object, so that transfer and fixing are performed (refer to PTL 1).
In addition, in recent years, a method has been disclosed in which an ultraviolet curable ink image is printed on a planar original plate by ink jet, UV irradiation is performed on the ultraviolet curable ink image, thereby making the ultraviolet curable ink image be in a half-dry state, the ultraviolet curable ink image in the half-dry state is transferred to the surface of an elastic blanket, the ultraviolet curable ink image transferred to the elastic blanket is offset-printed to a printing object, and the offset-printed ultraviolet curable ink image is dried and fixed (refer to PTL 2).